In Alias Grace, what did Grace mean when she said she'd rather be a murderess than a murderer, if those were the only two choices?

The answer to this question necessarily involves an
understanding of gender and the way that women were thought of and treated at the time
when the novel is set. Women were thought of as being fragile and weak and incapable of
committing crimes such as murder. Critics have noted the different treatment that Grace
Marks receives from the law compared to James McDermott, who was quickly found to be
guilty and hanged for murder. There was no discussion about his guilt or otherwise, and
some argue that this is because of gendered assumptions about what men and women can't
do. Grace herself recognises that being branded as a murderess is something that is
oppressive, but what she finds attractive about it is that there is a mystery, an
allure, that causes other people to treat her differently. Note what the quote
says:

It has
a smell to it, that word--musky and oppressive, like dead flowers in a vase. Sometimes
at night I whisper it over to myself: Murderess,
Murderess. It rustles, like a taffeta skirt across the
floor.

Murderer is merely brutal. It's
like a hammer, or a lump of metal. I would rather be a murderess than a murderer, if
those are the only
choices.

Grace decides that
she would rather be called a "murderess" than a "murderer" because of the associations
that go with that word. To be a "murderer" is to be "merely brutal," but to be a
murderess, although it brings its own challenges, is infinitely preferable, because of
the way that being a "murderess" goes against expected gender norms of the day and
therefore gives that person a kind of celebrity status.